Abstract

Background Little is known about the effects of overall diet in childhood and intelligence later in life.

Methods The current study, based on the Avon Longitudinal Study of Parents and Children, uses data on children's diet reported by
parents in food-frequency questionnaires at 3, 4, 7 and 8.5 years of age. Dietary patterns were identified using principal-components
analysis and scores computed at each age. IQ was assessed using the Wechsler Intelligence Scale for Children at 8.5 years.
Data on a number of confounders were collected, and complete data were available for 3966 children.

Results After adjustment, the ‘processed’ (high fat and sugar content) pattern of diet at 3 years of age was negatively associated
with IQ assessed at 8.5 years of age—a 1 SD increase in dietary pattern score was associated with a 1.67 point decrease in
IQ (95% CI −2.34 to −1.00; p<0.0001). The ‘health-conscious’ (salad, rice, pasta, fish, fruit) pattern at 8.5 years was positively
associated with IQ: a 1 SD increase in pattern score led to a 1.20 point increase in IQ (95% CI 0.52 to 1.88; p=0.001).

Conclusion There is evidence that a poor diet associated with high fat, sugar and processed food content in early childhood may be associated
with small reductions in IQ in later childhood, while a healthy diet, associated with high intakes of nutrient rich foods
described at about the time of IQ assessment may be associated with small increases in IQ.